Motor fuel



Patented Oct. 6, 1953 MOTOR FUEL Harry J. Andress, Jr., Woodbury, andFrederick L. Nelson, Pitman, N. J., assignors to Socony- Vacuum OilCompany, Incorporated, a corporation of New York No Drawing. ApplicationOctober 31, 1950, Serial No. 193,302

2 Claims. (Cl. 196-150) This invention relates, broadly to motor fuelscontaining pre-formed gum. It is more particularly concerned withdecreasing resinous deposits in an internal combustion engine which areproduced by such gum.

As is well known to those familiar with the art, virtually allgasolines, particularly those manufactured by pyrolytic processes, suchas by cracking and by polymerization, have a tendency to form polymericmaterials during storage. These materials are commonly known as gum.When present in the gasoline, the gum forms hard, resinous deposits inthe carburetor and the intake manifold, and on the valves of internalcombustion engines, particularly on the intake valves and the intakevalve ports. Obviously, such deposits are objectionable, since theydecrease the operating emciency of the engine and endanger theoperational life. Notably, the intake valves are prone to stick, causingpoor performance and reduced mileage, and even complete engine failure.

The exact nature of the gum-forming materials in gasolines is not wellknown. Gum-forming constituents may be removed by treatment of thegasoline with acids, such as sulfuric acid, with clay, and the like.Such processes are disadvantageous, since they decrease the octane valueof the fuel and increase refining costs. In U. S. Patent No. 2,066,234to Sloane and Wasson,

it was proposed to add certain lubricating oil stocks to gasoline toreduce valve-sticking and the like. The patentees specified that the oilshould have a Kauri-butanol number of at least 15, preferably over 20, a100 F. Saybolt viscosity of 70-450 seconds, an A. P. I. gravity of18-28, and a flash point of between 270 F. and 375 F. This definitionpoints toward a naphthenic, Coastal oil and excludes paraffinic oilshaving a low Kau-ri-butanol number.

It has now been found that the addition of small amounts of a certainhydrocarbon fraction, having no Kauri-butanol number, to a gasolinedecreases the formation of hard, gum deposits in an internal combustionengine in which it is used. It has now been discovered that when a smallamount of a petrolatum stock is added to a gasoline containing gum,valve-sticking is eliminated and excessive hard gum deposits arereduced.

Accordingly, it is an object of the present invention to reduce theamount of hard gum deposits in an internal combustion engine. Anotherobject is to provide a gasoline which will not cause valve-sticking andexcessive gum deposits when used in an internal combustion engine. Aspecific object is to provide a gasoline containing preformed gum towhich has been added a small amount of certain petrolatum stocks. Otherobjects and advantages of this invention will become apparent to thoseskilled in the art, from the following detailed description.

I The present invention provides a gasoline, normally tending to formhard gummy deposits and to cause valve-sticking when used in an internalcombustion engine, containing a small amount, sufficient to reduce saiddeposits and to eliminate valve sticking, of a petrolatum stock having aSaybolt Universal viscosity 210 F. of between about and about 125seconds, a melting point between about F. and about 135 F., an ASTMpenetration at 77 F. of between about 60 and about 110, and which isinsoluble in the Kauri-butanol solution at the test. temperatures. Theadditive which is effective for reducing gum deposits and valve stickingwhen added to a gasoline is a petrolatum stock having the followingproperties:

Penetration, AS'IM cone at 77 F- 60-110 The petrolatum is also insolublein the Kauributanol solution at the prescribed test temperature, usually75-80 F., used in determining the Kauri-butanol number. A preferredpetrolatum stock is one derived from a Mid-Continent crude, and havingan A. P. I. gravity of about 32 and melting at -135 F. The otherproperties of this petrolatum fall within the ranges set forthhereinbefore. It will be appreciated, however, that petrolatum stocksfrom other sources can be used. The main requisite for any petrolatumstock applicable herein is that it have the properties set forthhereinbefore.

The amount of petrolatum stock which is added to a gasoline to achievethe aforedescribed improved results is generally a function of thenature of the gasoline employed, i. e., the amount of harmful gumtherein. Ordinarily, the amount used is between about 0.05 per cent andabout 0.30 per cent, by volume, and preferably between about 0.15 andabout 0.25 per cent. In addition to the petrolatum stock, the gasolinesof this invention can contain minor amounts of other materialswell-known in the art, such as color- 13 ing matter, diluents, antiknockadditives, and the like.

The following specific example is for the purpose of illustrating thepresent invention, and of demonstrating the advantages thereof. It mustbe strictly urider'stood'that this' invention -is can to be limite d tothe 'particular'p'etrolatum *and gasoline employed, or to the operationsand manipulations set forth in the example. As those skilled in the artwill readily understand a w-ide variety of other petrolatums can beused, as set forth hereinbefore.

Example To a motor gasoline having the following properties:

ASTM distillation, F;

IBP All... .92 recovered "1'34 recovered 234 "recovered '35? EP A06 ALP.I. gravity 56.7 Gum, rag/1'00 ml: 7 V A 011 dish "6352 ASTM 12.4

was blended 0.25 per cent, by volume, of a petrolatum stock derived froma Wild-Continent crude.

This stockhadan AQP. I. gravity of 32.0'and. melted at 1'29-135 F. Itwas not soluble in the Kauri-butanol solvent at the temperatureprescribed for determining the Kauri-butanol number, i. e., at 83 F. Theblend thus-prepared was used as the fuel ina clean Wisconsinengineoperated for 11 hours at 1950B. P. M. with-anair-'fue1 ratio of111:1. .At the endof the run, the engine was dismantled and inspected.The'cleanliness of theenginewas rated. l he valve stem cleanliness was:goodand the valvehead cleanliness was very good.

addition of small amounts of the petrolatum stock defined herein togasolines markedly improves the gum depositing characteristics thereof.As will be apparent to those skilled in the art, such improvement willbe evident in any gasoline which' cor'itains 'preformediguhi.Accordingly, al- 'though the invention'has been illustrated with onegasoline, the use of other gasolines is contemplated herein. Thus, thegasoline can be a straight-run gasoline, a catalytically crackedgasoline, thermally cracked gasoline, thermally orca'talytieallymeformed gasoline, polyform gaso- T linejriaturalgasoline, or the like.

Although the' present invention has been described with preferredembodments, it is to be understood that modifications and variations maybe. resorted to without departing from the spirit and scope thereof, asthose skilled in the art will r'adilyunderstand. Such variations andmodifications are considered to be within the pur- -view ahd scope ofthe appended claims.

" What is claimed is:

ilun'imotortiuel which comprises a gasoline, normally tending toiformhard" gummy de osits 2 and to cause valve sticking when used in anintern'al combustion engine, .fc'o'ntaining between about 0.05% .andabout 0.30%, by volume, of a ipetrolatum stock having a SayboltUniversal viscosity at "210 F. of between about and about--l25.second's, "a melting point of between about :F. and' -about anAS'TM penetration at 77 F. or" between about'60 aridabout'llQand"which-has no Kauri-butanol number.

2. Amotorfuel as defined in claim -1,'wherein 5 saidpetrola'tumistock-isderived'from a Mid Continentcrude oil.

HARRY JVANDRESS, 'JR. FREDERICK L. NELSON.

40 :References Cited in-the file of this patent UNITED STATES PATENTSNumber Name Date 1,325,907 Petteyet a1. 'Dec. 23,1919 45 1,826,439'Stryker Oct. 6, 1931 2,066,234 Sloane et'alr Dec. 29, 1936 92,125,875Barnard Aug. 9, 1938 2,318,710 Persyn May 11, 1943 "2,368,482'Mathie'sen Jan. 30, 1945

1. A MOTOR FUEL WHICH COMPRISES A GASOLINE, NORMALLY TENDING TO FORMHARD GUMMY DEPOSITS AND TO CAUSE VALVE STICKING WHEN USED IN AN INTERNALCOMBUSTION ENGINE, CONTAINING BETWEEN ABOUT 0.05% AND ABOUT 0.30%, BYVOLUME, OF A PETROLEUM STOCK HAVING A SAYBOLT UNIVERSAL VISCOSITY AT210* F. OF BETWEEN ABOUT 95 AND ABOUT 125 SECONDS, A MELTING POINT OFBETWEEN ABOUT 115* F. AND ABOUT 135* F., AT ASTM PENETRATION AT 77* F.OF BETWEEN ABOUT 60 AND ABOUT 110, AND WHICH HAS NO KAURI-BUTANOLNUMBER.